<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin:0;
            padding:0;
        }
        .box{
            height:400px;
            width:1000px;
            background-color: red;
        }
        .a{
            height:300px;
            width:300px;
            background-color: green;
            float:left;
        }
        .b{
            height:300px;
            width:300px;
            background-color: purple;
            float:left;
        }
        .d{
            height:100px;
            width:600px;
            background-color: rgb(78, 210, 170);
            float:left;
        }
        .c{
            height:150px;
            width:400px;
            background-color: rgb(151, 145, 147);
        }
        .e{
            height:250px;
            width:400px;
            background-color: rgb(9, 224, 70);
        }
        .leftbox{
            height:400px;
            width:600px;
            float:left;
        }
        .rightbox{
            height:400px;
            width:400px;
            float:right;
        }
    </style>
</head>
<body>
    <div class="box">
        <div class="leftbox">
          <div class="a">a</div>
          <div class="b">b</div>
          <div class="d">d</div>
        </div>
        <div class="rightbox">
            <div class="c">c</div>
            <div class="e">e</div>
        </div>
    </div>
</body>
</html>